CVE-2026-32136
AdGuard Home: HTTP/2 Cleartext (h2c) Upgrade Authentication Bypass
CVSS Score
9.8
EPSS Score
0.0%
EPSS Percentile
0th
AdGuard Home is a network-wide software for blocking ads and tracking. Prior to 0.107.73, an unauthenticated remote attacker can bypass all authentication in AdGuardHome by sending an HTTP/1.1 request that requests an upgrade to HTTP/2 cleartext (h2c). Once the upgrade is accepted, the resulting HTTP/2 connection is handled by the inner mux, which has no authentication middleware attached. All subsequent HTTP/2 requests on that connection are processed as fully authenticated, regardless of whether any credentials were provided. This vulnerability is fixed in 0.107.73.
| CWE | CWE-287 |
| Vendor | adguardteam |
| Product | adguardhome |
| Published | Mar 11, 2026 |
| Last Updated | Mar 12, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
AdguardTeam / AdGuardHome
< 0.107.73